Mutant of transcriptional regulation factor BgaR and application thereof

The invention relates to a novel transcription regulation factor BgaR mutant, and belongs to the field of metabolic engineering. The mutant is obtained by mutation of P120L, I123 V, S187N and Y226C on the basis of wild type BgaR derived from clostridium perfringens, and has an amino acid sequence as shown in SEQ ID NO. 1. According to the invention, the BgaR is used as a recognition element in the biosensor for the first time to construct the lactose biosensor, so that the lactose concentration is coupled with the growth condition of a strain, and the lactose content in cells is measured/represented; according to the present invention, the lactose biosensor with characteristics of high lactose sensitivity and wide response range is obtained by optimizing the BgaR, the lactose response range after the BgaR mutation is increased from 5-10 g/L to 0-12 g/L, and when the lactose concentration is 12 g/L, the growth condition of the BgaR mutant expression strain is significantly superior to the growth condition of t